Devices and methods for hip replacement

ABSTRACT

A device for use in placing a prosthesis in a patient during joint replacement surgery is disclosed. The device may comprise a body formed using medical imaging data corresponding to an anatomic structure of the patient and a final installation position of the prosthesis. The body may extend between a lower surface and an upper surface and may have an aperture extending therethrough. The body may also have an anatomic alignment member extending outward from an outer surface of the body and include an inner surface opposite the outer surface. The inner surface may define at least part of the aperture. The prosthesis alignment member may extend from the inner surface and the prosthesis alignment member may include a prosthesis alignment surface configured to align with a prosthesis in the final installation position.

CROSS-REFERENCE

This application is a continuation of U.S. application Ser. No.14/485,074, filed Sep. 12, 2014, now U.S. Pat. No. 9,414,938, issuedAug. 16, 2016, which is incorporated herein by reference in its entiretyand to which application we claim priority under 35 USC § 120.

BACKGROUND

Technical Field

The present disclosure relates to devices and methods for thereplacement of joints, and more particularly, to patient-specific hipreplacement devices, including methods of manufacturing and using suchdevices for achieving accurate placement of prosthetics based oncomputer generated imaging of a patient.

Description of the Related Art

One method of treating hip and other joints with arthritis and othermedical conditions is to replace surfaces of articulating joints withprosthetic devices through surgical procedures. It is critical that suchprosthetic devices are accurately designed and manufactured, and areinstalled correctly in order to relieve pain and provide an effectivetreatment method for such ailments. An orthopedic surgeon performingsuch joint replacement on a patient seeks to ensure, through surgery,adequate placement of the prosthetic and proper reconstruction of thejoint being replaced. A particular patient's bone structure symmetry andkinematics are things a surgeon considers when performing jointreplacement surgery. Malposition of joint replacement prosthetics canresult in premature wear of the bearing surfaces, which may requireadditional surgeries to correct.

In the case of a hip, the condition of the patient's joint may require apartial or total replacement. A partial hip replacement involvesreplacing the femoral head (the ball) of the damaged hip joint; however,the acetabulum (the hip socket) is not replaced in a partial hipreplacement surgery. A total hip replacement includes replacing both thefemoral head and the acetabulum with prosthetic devices. The femoralhead is replaced with a femoral prosthetic that typically includes ahead portion and a stem. The stem extends into the femur of the patientand is utilized to secure the femoral device to the femur, with the headportion protruding out from the femur. In total hip replacement, theacetabulum is resurfaced and replaced with a cup-shaped acetabulardevice or prosthetic. The cup-shaped acetabular device provides abearing surface for the head portion of the femoral prosthetic to allowa desirable amount of range of motion via the joint upon total hipreplacement.

To replace the acetabulum effectively, a surgeon will typically enlargethe acetabulum with a reamer machine and reamer head to create aresurfaced cavity to receive a prosthetic acetabular cup, which may ormay not be secured by cement or bone screws. One concern during thereaming portion of the surgery is that the cutting portion of the reameris hemispherical while the prosthetic acetabular cup is typicallysub-hemispherical. If the acetabulum is reamed too deeply, theprosthetic acetabular cup will be positioned too deep within the reamedcavity. If the acetabulum is reamed too shallowly, the prostheticacetabular cup will not be positioned deep enough. If the acetabulum isreamed at an improper angle, the prosthetic acetabular cup will not beinstalled properly. These imperfections can cause malalignment of theprosthetic hip joint. Moreover even if the acetabular bone is properlyreamed, it is quite difficult to place the acetabular prosthetic cupwhen using standard techniques. Recent studies reflect a 50% rate oferror in placement of the acetabular cup from an acceptably optimalrange of positions when standard techniques are utilized. Thus, accuratereaming of the acetabulum and accurate positioning of the prostheticacetabular cup are critical.

With the assistance of computer generated data derived from CT, MRI, orother scans, such as X-rays, surgeons can more effectively determineproper alignment and positioning of the prosthetic acetabular cup in apatient through 3-D modeling and rendering. Some surgeons use lasers orperipheral guide pins during surgery in an attempt to properly place theprosthetic acetabular cup; however, accuracy and simplicity of existingdevices and methods remain limited due to a variety of factors.

BRIEF SUMMARY

A device for use in placing a prosthesis in a patient during jointreplacement surgery is disclosed. The device may comprise a firstcomponent formed using medical imaging data corresponding to an anatomicstructure of the patient and a final installation position of theprosthesis and a second component formed using medical imaging datacorresponding to the anatomic structure of the patient and the finalinstallation position of the prosthesis. The first component may have afirst body extending between a lower surface and an upper surface and anaperture extending therethrough. The first component may also have ananatomic alignment member extending outward from an outer surface of thefirst body. The anatomic alignment member may have a first alignmentsurface shaped to conform to an anatomic structure of the patient. Theaperture may be at least partially defined by an inner surface extendingbetween the upper surface and lower surface and the inner surface may besized and shaped to receive the second component. The second componentmay include a an upper portion and a lower portion. The upper portionmay be joined to the lower portion at an alignment rim sized and shapedto mate with a rim of the prosthesis and the lower portion may have asurface sized and shaped to conform to at least part of an internalsurface of a prosthesis.

Another device for use in placing a prosthesis in a patient during jointreplacement surgery is also disclosed. The device may comprise a bodyformed using medical imaging data corresponding to an anatomic structureof the patient and a final installation position of the prosthesis. Thebody may extend between a lower surface and an upper surface and mayhave an aperture extending therethrough. The body may also have ananatomic alignment member extending outward from an outer surface of thebody and include an inner surface opposite the outer surface. The innersurface may define at least part of the aperture. The prosthesisalignment member may extend from the inner surface and the prosthesisalignment member may include a prosthesis alignment surface configuredto align with a prosthesis in the final installation position.

A method for replacing a joint of a patient may be disclosed. The methodmay include generating a bone surface image. A prosthesis imagesuperimposed on the bone surface image in an installation position ofthe prosthesis may be generated. A patient specific jig imagesuperimposed proximate the bone surface image and the implant imageaccording to the installation position of the prosthesis may begenerated. The patient specific jig image may include a body including alower surface and an opposite upper surface and having an apertureextending between the upper surface and the lower surface. The body mayinclude a prosthesis alignment member extending from the inner surface.The prosthesis alignment member may include a prosthesis alignmentsurface configured to align with the prosthesis image in the finalinstallation position. The method may also include generating controldata from the patient specific jig image.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts a method according to one or more embodiments disclosedherein;

FIG. 2 depicts a system according to one or more embodiments disclosedherein;

FIG. 3 depicts a method according to one or more embodiments disclosedherein;

FIG. 4 depicts a method according to one or more embodiments disclosedherein;

FIG. 5 depicts a front view of a pelvic bone with an installedacetabular prosthesis according to one or more embodiments disclosedherein;

FIG. 6 depicts a top view of a pelvic bone of FIG. 5 with an installedacetabular prosthesis according to one or more embodiments disclosedherein;

FIG. 7 depicts an exploded view of a device for hip replacementaccording to one or more embodiments disclosed herein;

FIG. 8 depicts a cross-sectional view of a device for hip replacementaccording to one or more embodiments disclosed herein;

FIG. 9 depicts a top view of a device for hip replacement according toone or more embodiments disclosed herein;

FIG. 10 depicts a cross-sectional view of the device for hip replacementof FIG. 9;

FIG. 11 depicts a cross-sectional view of the device of FIG. 9 installedaccording to one or more embodiments disclosed herein;

FIG. 12 depicts a top view of a device for hip replacement according toone or more embodiments disclosed herein; and

FIG. 13 depicts a cross-sectional view of the device for hip replacementof FIG. 12.

DETAILED DESCRIPTION

The present disclosure pertains to patient-specific hip replacementdevices and methods for designing and manufacturing such devices forachieving accurate acetabular component placement during hip replacementsurgery based on computer generated imaging of a particular patient.When an orthopedic surgeon recommends total hip replacement surgery fora particular patient, a variety of images may be obtained utilizing CT,MRI, and other scans, such as x-rays, to generate 3-D modeling of thepatient's bone structure, particularly the femur, the pelvic bone, andthe coxal (hip) bone. From such 3-D models, the surgeon may determinethe specific, final location and orientation of an acetabular cup to besecured to the patient's acetabulum during surgery. Once the finallocation and orientation of the acetabular cup is determined, thesurgeon may create a patient-specific jig to be installed on thepatient's acetabulum during the surgery to achieve or confirm accuratepositioning of the prosthetics installed in the patient.

The patient-specific jig may be designed and manufactured based on apatient-specific acetabulum. The patient-specific jig can be developedas either physical components via a prototyping machine or visualrepresentations in a 3-D modeling software program based upon the 3-Dimages of the patient.

The methods and systems disclosed herein are based at least in part onpre-operating (preoperative) imaging and at least in part on orthopedicsurgical procedures based upon the preoperative methods and systems. Asis understood in the art, preoperative imaging has a number of differentpurposes and generally is performed to help guide the surgeon during thesurgical procedure, to allow for patient-specific tools or implants tobe formed, etc. The present disclosure may be part of a system fordesigning and constructing one or more patient-specific jigs for use inan orthopedic surgical procedure in which an acetabular component isprepared, oriented, and implanted. The referenced systems and methodsare now described with reference to the accompanying drawings, in whichone or more illustrated embodiments or arrangements of the systems andmethods are shown in accordance with one or more embodiments disclosedherein. Aspects of the present systems and methods can take the form ofan entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.), or anembodiment combining software and hardware. One of skill in the art canappreciate that a software process can be transformed into an equivalenthardware structure, and a hardware structure can itself be transformedinto an equivalent software process. Thus, the selection of a hardwareimplementation versus a software implementation is one of design choice,and is left to the implementer. Throughout this disclosure, the term“prosthetic implant” and “acetabular component” refer to cup-shapedimplants that are installed into patients during hip replacementsurgery.

FIG. 1 is a flow diagram illustrating a method pertaining topreoperative imaging and planning according to aspects of the presentdisclosure. FIG. 2 shows a system for carrying out the methods of thepresent disclosure, such as that described with reference to FIG. 1.FIG. 2 shows a simplified system 210 of devices that may be used tocarry out the methods of the present disclosure. The system 210comprises a computing system 212 coupled to an imaging system 214. Theimaging system 214 captures patient image data and transfers the data tothe computing system 212. The computing system 212 processes such dataand transmits the data to a display device 216 for display of images andother data. An input device 218 receives input from a computer or anoperator (such as a surgeon) and transmits inputted information to thecomputing system 212 for processing. Such input devices 218 are wellknown in the art and will not be described in greater detail. Theimaging system 214 may include a bone imaging machine for formingthree-dimensional image data from a bone structure of a patient. Thecomputing system 212 may include a patient-specific device generator forprocessing and generating images, and a patient-specific deviceconverter for generating design control data. A manufacturing machine220 receives the control data from the computing system 212 for makingpatient-specific jigs.

In FIG. 1, a method 100 according to an embodiment may start at block102. At block 102, a bone imaging machine generates a bone surface imagefrom three-dimensional image data from the bone structure of a patient.At block 104, a patient-specific device generator generates a prosthesisimage superimposed on an acetabulum of the bone surface image. Theprosthesis image is positioned in its final, implanted position andorientation, regardless of the state of the patient's bone in the bonesurface image. An outer surface of the prosthesis image may determinethe surface of the reamed acetabulum of the patient. For example, byplacing the prosthesis image in the final, implanted position andorientation, a doctor may determine the final shape and orientation ofthe reamed acetabulum such that a prosthesis may be inserted orimplanted into the patient's reamed acetabulum in the correct final,implanted position and orientation. The jigs created from the presentdisclosure may be designed to install or confirm proper installment of aprosthesis during a hip replacement procedure.

At block 106, the patient-specific device generator generates a patientspecific jig image superimposed proximate the acetabulum of the bonesurface image and the prosthesis image according to the installationposition. The patient-specific device generator may use the bone surfaceimage to create a patient-specific device with anatomic engagementmembers that have an engagement surface that corresponds to, matches, oris the negative contour of the patient's anatomy. The patient-specificdevice generator may use the prosthesis image to generate prosthesisengagement members that engage with features of the prosthesis, such asa surface or rim of the prosthesis. The patient-specific devicegenerator may also use the prosthesis image and the bone surface imageto generate jig alignment features or members.

At block 108, a patient-specific device converter generates control datafrom the patient-specific jig image. The control data may be used by amachine during a manufacturing process to create physicalpatient-specific jigs by additive or subtractive machining, such asfused deposition modeling, stereolithography, or other methods. At block110, the manufacturing device creates a physical patient-specific jig.

As discussed above, FIG. 2 shows the system 210 for carrying out themethods of FIG. 1 according to some aspects of the present disclosure.The computing system 212 may include instructions in the form ofcomputer software for automatically generating images of prosthesisimplants in final installation positions on the bone structure images.In some aspects, it may be necessary for the surgeon during preoperativeplanning to input information into the input device 218 for creating oraltering jig images or prostheses images for a particular patient basedon the surgeon's understanding of the particular bone structure of thepatient as displayed on the display device 216.

FIGS. 3 and 4 are flow diagrams of methods pertaining to operativesurgery according to aspects of the present disclosure. The methods ofFIGS. 3 and 4 may be carried out by a surgeon or by a machine, or byboth. Moreover, the process may utilize some or all of the devicesdiscussed with reference to FIGS. 1 and 2 during surgery, such asviewing the preoperative images displayed on the display device whileoperating on a patient.

In FIG. 3, a method 300 according to an embodiment disclosed herein maystart at block 302. The method 300 may be carried out using a patientspecific jig, such as, for example, shown in FIGS. 9-13. In hipreplacement procedures, almost all patients have their acetabulumreshaped to accept a prosthetic acetabulum. The acetabulum may be reamedor otherwise reshaped to accept the prosthesis in any manner. Once adoctor or machine shapes the acetabulum to the correct shape, at block302, the prosthesis is inserted into a reamed acetabulum of a patient. Adoctor may insert the prosthesis by hand, using an impactor tool, orusing another tool to insert the prosthesis. A reamed acetabulum may bereamed to have a radius or shape that is slightly smaller than theradius or shape of the acetabular component. As such, the surgeontypically utilizes a mallet or other tool to impact the prosthesis intoits final position. In some embodiments, the doctor may place theprosthesis into the reamed acetabulum in a position and orientationapproximate the final implantation position and then use an impactortool to place the prosthesis in its final position.

At block 304, a doctor or machine may place a patient specific jigadjacent an acetabulum of a patient, the patient specific jig formedaccording to a predetermined installation position of the prosthesis tobe secured to the patient and three-dimensional image data from the bonestructure of a patient. Placing the patient specific jig may includealigning an anatomical alignment member of the patient specific jig tocorresponding pre-selected areas adjacent or peripheral the acetabulumof the patient and also aligning a prosthesis alignment member with theprosthesis. For example, after placing the prosthesis into the reamedacetabulum by hand, a doctor may position the patient specific jig andalign, but possibly not engage, the various alignment members of thepatient specific jig with anatomical features adjacent an acetabulum ofa patient and the prosthesis. By positioning the jig in such a manner,the doctor may evaluate the initial position of the prosthesis and maymake adjustments to the initial position of the prosthesis beforeattempting to place the prosthesis in its final or predeterminedinstallation position.

At block 306, a doctor or machine may attempt to engage an anatomicalalignment member of the patient specific jig corresponding topre-selected areas adjacent to or on the periphery of the acetabulum ofthe patient. And at block 308, a doctor or machine may attempt to engagea prosthesis alignment member with the prosthesis.

If the acetabular prosthesis has been placed in the correct finalinstallation position, the anatomical alignment member of the patientspecific jig should engage with the corresponding to pre-selected areasadjacent or peripheral the acetabulum of the patient, and the prosthesisalignment member should engage with the acetabular prosthesis. Thus, atblock 310, a doctor or machine may inspect the alignment and engagementof the alignment members and determine whether the anatomical alignmentmember of the patient specific jig is engaged to the pre-selected areasadjacent or peripheral the acetabulum of the patient, and the prosthesisalignment member is engaged with the prosthesis. If the alignmentmembers are properly engaged, then the acetabular prosthesis isinstalled in the correct installation position and orientation. If thealignment members are not properly engaged, then the acetabularprosthesis is not in the correct final installation position.

Furthermore, an evaluation of the engagement members relative to thepatient's anatomy or the acetabular prosthesis may help quantifydisplacement of the current position of the acetabular prosthesis withthe final installation position of the acetabular prosthesis. Forexample, by looking at the alignment members and their positionsrelative to the prosthesis and the patient's anatomy, a doctor maydetermine how far the prosthesis should be rotated or how much deeperthe prosthesis should be driven into the patient's acetabulum in orderto place the prosthesis in the final installation position.

At block 312, a doctor or machine may adjust the position of theacetabular prosthesis. Once the adjustment is complete, the process mayreturn to block 306. In some embodiments, the process may return toblock 304 or block 308. In addition, in some embodiments, depending, forexample, on the steps a doctor or machine uses to adjust the positionand orientation of the prosthesis at block 312, one or more of blocks304, 306, or 308 may be omitted. In some embodiments, the position andorientation of the prosthesis may be such that the prosthesis should beremoved and the process may begin again at block 302.

In FIG. 4, a method 400 according to an embodiment disclosed herein maystart at block 402. The method 400 may be carried out using a patientspecific jig, such as, for example, shown in FIGS. 7 and 8. At block402, a doctor may position a first patient specific jig componentadjacent an acetabulum of a patient. The patient specific jig may beformed according to a predetermined installation position of theprosthesis to be secured to the patient and three-dimensional image datafrom the bone structure of a patient. Positioning the first patientspecific jig component may also include engaging an anatomic alignmentmember with the anatomic structure adjacent the acetabulum of thepatient.

At block 404, a doctor or machine may couple a prosthesis to a secondpatient specific jig component. In some embodiments, for example, asshown in the embodiment depicted in FIGS. 7 and 8, a surface of thesecond patient specific jig component may match an inner surface of theacetabular prosthesis such that, by pressing the acetabular prosthesisonto the second patient specific jig component, the jig component holdsthe prosthesis.

At block 406, the second patient specific jig component and theprosthesis are inserted into the patient's reamed acetabulum. In someembodiments, the second patient specific jig component and theprosthesis are inserted while coupled together, for example, inembodiments where the prosthesis is coupled to the second patientspecific jig before being inserted into the acetabulum. In someembodiments, the acetabular prosthesis may be inserted into the reamedacetabulum before the second patient specific jig component is inserted.

At block 408, the second patient specific jig component is aligned withthe first patient specific jig component. The alignment of the two jigsindicates that the acetabular prosthesis is installed in the correctfinal installation position, as determined during the preoperativeanalysis. In some embodiments, a doctor may align the two jig componentsby using an impactor tool to drive the acetabular prosthesis into thereamed acetabulum and into the final installation position. As describedelsewhere in this disclosure, the first and second patient specific jigcomponents may be aligned in a number of different ways. In someembodiments, alignment keys may be used to align and verify correctalignment of the jigs; in some embodiments, a surface of the first jigcomponent may align with the surface of the second jig component. Insome embodiments, a mark, surface indicator, or other indicator may beused on one or both of the first and second jig components to aid inalignment.

FIGS. 5 and 6 show an acetabular component 500 oriented in an acetabulum502 of a coxal bone 504 of a pelvic bone 506. The acetabular component500 is positioned according to an installation position 508, which is inpart determined by a prescribed anteversion angle and a prescribedinclination angle of the acetabular component 500. FIG. 5 shows a frontview of the pelvic bone 506 and the acetabular component 500 positionedin the acetabulum 502 of the patient's right coxal bone 504, and FIG. 6shows a lateral view of the right coxal bone 504 with the acetabularcomponent 500 positioned in the acetabulum 502. These figures illustratethe incorporation of the methods and devices discussed herein where theacetabular component 500 may be a generated image that is superimposedover a generated image of bone structure or patient anatomy (e.g., thecoxal bone 504) of a patient to determine an installation position 508of the acetabular component 500. FIGS. 5 and 6 may also represent aphysical acetabular component or prosthesis installed in a finalinstallation position in a patient's actual coxal bone.

Determining the prescribed anteversion angle and the prescribedinclination angle for a particular patient involves techniques andcalculations that are known in the art, and thus, will not be describedin detail. Although not necessarily part of the preoperative planning,for purposes of illustration an installation axis P is shown on FIG. 5.

Once the installation position 508 is determined, a reference point 510is established that represents a particular point in the coxal bone 504of the patient for purposes of determining the depth to which a reamingmachine will ream bone material. The reference point 510 may beconsidered a point on the tangential plane of a hemispherical shapedsurface, such as the outer surface shape of the acetabular component500.

With continued reference to FIGS. 5 and 6, the coxal bone 504 includes,among other anatomical features, a medial rim 512, a sciatic notch 514,and an obturator foramen 516, which all have various shapes and surfacesthat are specific to each patient. The anatomical features including themedial rim 512, the sciatic notch 514, and the obturator foramen 516 arepotential anatomic reference features to which alignment members of apatient specific jig may align or engage.

FIGS. 7 and 8 depict a device for hip replacement, a prosthesis, and across section of a coxal bone. FIG. 7 shows an exploded view of thedevice and prosthesis while FIG. 8 shows a cross section of the deviceand prosthesis in a final installation position within a patient'sreamed acetabulum. The device for hip replacement includes a firstpatient specific jig component 600 that aligns with or engages with theanatomic structure of a patient and a second patient specific jigcomponent 700 that aligns with the first patient specific jig component600 and a prosthesis 800 to place the prosthesis 800 into the reamedacetabulum 502 of the patient.

The prosthesis 800 is a replacement acetabulum that a doctor insertsinto the reamed acetabulum of a patient in a full hip replacementoperation. The prosthesis 800, or acetabular cup, includes an outersurface 810 that matches the reamed surface 518 of the acetabulum 502.In some embodiments, the outer surface 810 of the prosthesis 800 islarger than the reamed acetabulum such that the prosthesis 800 isforced, hammered, pressed, or otherwise press fit into the acetabulum ofa patient and held in place by an outward force of the prosthesis 800 onthe reamed acetabulum 502. The inner surface 820 defines the inside ofthe prosthesis 800. An inner surface 820 is shaped to accept aprosthetic femoral head, not shown. The prosthesis 800 may also includea rim 830. The rim 830 may function as a reference location used todetermine whether the prosthesis 800 is at a final installationposition.

The first patient specific jig component 600 includes a body 602 and aradially or outwardly extending alignment member 610. In someembodiments, the body 602 may be circular or annularly shaped with acentral aperture 630. The body 602 includes an alignment surface 620.The alignment surface 620 may be shaped to match the rim of theacetabulum 502 such that the surface 620 and, therefore, the body 602may align with the anatomic structure of a patient in one position ororientation. The alignment member 610 also includes an alignment surface612 that conforms or matches the anatomic surface structure 520 of apatient. For example, one or more alignment members 610 may align orengage with a point or area of the medial rim 512, the sciatic notch514, the obturator foramen 516, or other surfaces or contact points.

The aperture 630 of the body 602 is defined by a guide surface 632, alsocalled an aperture wall. The guide surface 632 may be concentric aroundthe installation axis P. The guide surface 632 matches a jig alignmentsurface 770 of the second component 700. In some embodiments, the guidesurface 632 is sized and shaped to accept the second patient specificjig component 700. In some embodiments, the aperture 630 or the guidesurface may be sized and shaped such that the second patient specificjig component 700 can be inserted into the aperture 630 in only a singleorientation.

The second patient specific jig component 700 may include an upperportion 705 and a lower portion 703. The lower portion 703 may include amating surface 720 that extends from the upper portion 705 and is sizedand shaped to match the inner surface 820 of the prosthesis 800, and mayhave a hemispherical shape. In other embodiments, only a portion of themating surface 720 is sized and shaped to match the inner surface of theprosthesis 800. The mating surface 720 may be inserted into the reamedacetabulum 502 of a patient during placement of the prosthesis.

The second component 700 also includes the upper portion 705, whichextends from an upper end of mating surface 720. The upper portion 705may include alignment features 750, 770. The upper portion 705 and themating surface 720 intersect at a rim 730 that extends around some orall of the second component 700. The rim 730 is shaped to match at leasta portion of the rim 830 of the prosthesis 800.

The rim 730 may help align and place the prosthesis 800 in a finalinstallation position. An acetabular prosthesis such as the prosthesis800 may have a hemispherical shape of a known diameter. Thus, by knowingthe position and orientation of the rim 830, a doctor can know theposition and orientation of the prosthesis 800 and, in particular, theposition and orientation of its inner surface 820.

The upper portion 705 may also include the cylindrically shaped jigalignment surface 770. The jig alignment surface 770 is sized and shapedto slidingly engage with the guide surface 632 of the first portion ofthe patient specific jig component 600. The jig alignment surface 770and guide surface 632 may engage such that they align the central axisof the prosthesis 800 with the installation axis P of the finalinstallation position of the prosthesis.

The upper portion 705 may also include a depth alignment feature, forexample, the alignment surface 750. The alignment surface 750 may alignwith an alignment surface 640 to indicate that the prosthesis 800 is atthe correct depth according to the final installation position of theprosthesis. For example, as a doctor places the prosthesis 800 and thesecond component through the first patient specific jig component 600and into the acetabulum 502, the doctor can monitor the relativeposition of the depth alignment surface 750 of the second component 700with the alignment surface 640 of the first component. When the twoalignment surfaces 750, 640 are coplanar, the doctor will know that theprosthesis 800 is at the correct depth according to the finalinstallation position. In other embodiments, the alignment surfaces 750,640 may be at different locations or, rather than being coplanar toindicate information, such as the depth of the prosthesis 800, to thedoctor, the two alignment surfaces may contact each other to indicateinformation to the doctor.

As shown in FIG. 8, the second component 700 may include a hollow innerarea or cavity 740. Using a cavity 740 may save weight as compared to ajig with a solid inner area. The second component 700 may also include amember 742 that extends from the cavity 740. The member 742 may extendout from the cavity 740 and beyond the alignment surface 750. The member742 may include a gripping surface 744 for the doctor to hold whileinserting the second component 700 through the aperture 630 in the firstpatient specific jig component 600 and into the reamed acetabulum 502 ofthe patient. In some embodiments, the member 742 may include an impactsurface, such as impact surface 746. A doctor may use a mallet or otherimpact device to install the prosthesis 800 by striking the impactsurface 746 with the mallet or other impact device.

Referring now to FIGS. 9-11, an embodiment of a device for installingand verifying the installation position of a prosthesis is shown. Thedevice is a patient specific jig 900. The patient specific jig 900includes a body 902 and a radially extending anatomic alignment member910 and may be circular or annularly shaped with a central aperture 930.The body 902 includes one or more anatomic alignment members 910 and oneor more prosthesis alignment members 940. The anatomic alignment member910 also includes an alignment surface 912 that conforms or matches theanatomic surface structure 520 of a patient. For example, one or morealignment members 910 may align or engage with a point or area on themedial rim 512, the sciatic notch 514, the obturator foramen 516, orother surfaces (see FIGS. 6 and 7). The alignment surface 912 mayinclude a surface shape or contours that match the surface shape orcontours of the anatomic structure with which the anatomic alignmentmember 910 aligns.

The shape and contours of the alignment surface 912 may be determinedbased upon the 3-D modeling images of the patient, a combination oftwo-dimensional radiographic images of the patient, or a combination ofthree-dimensional and two-dimensional images of a patient. The shape ofthe surface 912 is sometimes referred to as a negative of the anatomicstructure with which the surface 912 aligns or engages. It is a negativebecause, for example, a protrusion on the anatomic surface structure 520corresponds to a depression on the alignment surface 912 while adepression on the anatomic surface structure 520 corresponds to aprotrusion on the alignment surface 912. Although depicted as having asingle alignment member with a single alignment surface, in someembodiments, a patient specific jig may have more than one alignmentmember and alignment surface.

The body 902 includes an alignment surface 920. The shape and contoursof the alignment surface 920 may be determined based upon the 3-Dmodeling images of the patient, a combination of two-dimensionalradiographic images of the patient, or a combination ofthree-dimensional and two-dimensional images of a patient. The alignmentsurface 920 may be shaped to match the rim of the acetabulum 502 suchthat the surface 920 contacts the anatomic structure around the entireacetabulum. By aligning the alignment surface 920 with a point or areasurrounding the acetabulum 502, the body 902 may align with the anatomicstructure of a patient.

A patient specific jig may include one or more prosthesis alignmentstructures. For example, the patient specific jig 900 includes threeprosthesis alignment members 940 that extend from the body 902. Theprosthesis alignment members 940 include an alignment surface 942. Theshape and contours of the alignment surface 942 may be determined basedupon the 3-D modeling images of the patient, a combination oftwo-dimensional radiographic images of the patient, or a combination ofthree-dimensional and two-dimensional images of a patient. For example,a patient-specific device generator may generate a prosthesis image inits final implanted position and orientation and then generate a patientspecific jig corresponding to the final implanted position. In such anembodiment, the anatomic alignment members 910 and their correspondinganatomic alignment surfaces 912 may be generated to align or engage withthe anatomic structures of the patient near the acetabulum while theprosthesis alignment members 940 and their corresponding alignmentsurfaces 942 may be generated to align with the rim and a prostheticacetabulum when in the final implanted position. In this way, a doctormay use a physical patient specific jig manufactured according to thefinal installation position of the prosthesis and the patient's specificanatomic structure.

A doctor may use a patient specific jig, such as the patient specificjig 900, during a hip replacement operation. For example, after reamingor otherwise preparing a patient's acetabulum, the doctor may insert theprosthetic acetabulum into to the patient's acetabulum and attempt toplace it in a final installation position and orientation. After placingthe prosthetic, a doctor may align or engage the patient specific jig,such as patient specific jig 900, with the anatomic structure of thepatient and then observe the alignment or misalignment of the prostheticalignment structures and prosthetic alignment surfaces with the rim orother portion of the prosthetic. The alignment or misalignment of theprosthetic alignment surfaces with the rim or other portion of theprosthetic indicate information to the doctor regarding the position ofthe prosthetic. For example, if the prosthetic alignment surfaces alignwith the rim of the prosthetic, then a doctor may know that theprosthetic is in its final installation position, while misalignedalignment surfaces and rim may indicate how the position of theprosthetic should be changed to move the prosthetic into the finalinstallation position. For example, the misalignment of the surfaces mayindicate that the prosthetic should be set further into the reamedacetabulum of the patient, or the misalignment may indicate that theprosthetic's central axis is not in the correct orientation and theprosthetic should be tilted to align the central axis with theinstallation axis.

FIG. 11 shows a cross section of a coxal bone 504 with an installedprosthetic 1100 and an engaged patient specific jig 900. In thisembodiment, the anatomic alignment member 910 is engaged with acorresponding portion of the patient's anatomic surface structure 520,and the prosthetic alignment member 940 is engaged with the rim 830 ofthe prosthesis. This arrangement indicates that the prosthesis 800 is ina final installation position.

Referring now to FIGS. 12 and 13, an embodiment of a device forinstalling and verifying the installation position of a prosthesis isshown. The device is a patient specific jig 1200. The patient specificjig 1200 includes a body 1202 and a radially extending anatomicalignment member 1210 and may be circularly or annularly shaped with acentral aperture 1230. The body 1202 includes one or more anatomicalignment members 1210 and one or more prosthesis alignment members1240. The anatomic alignment member 1210 also includes an alignmentsurface 1212 that conforms or matches the anatomic surface structure ofa patient. For example, the alignment member 1210 shown in FIGS. 12 and13 extends around the entire circumference of the patient specific jig1200 and therefore may align or engage with the anatomic structure ofthe patient in the area surrounding the patient's acetabulum. Thealignment surface 1212 may include a surface shape or contours thatmatch the surface shape or contours of the anatomic structure with whichthe anatomic alignment member 1210 aligns.

The shape and contours of the alignment surface 1212 may be determinedbased upon the 3-D modeling images of the patient, a combination oftwo-dimensional radiographic images of the patient, or a combination ofthree-dimensional and two-dimensional images of a patient.

The patient specific jig 1200 may include one or more prosthesisalignment members 1240. For example, the patient specific jig 1200includes a single prosthesis alignment member 1240 that extends from thebody 1202. The prosthesis alignment member 1240 includes an alignmentsurface 1242. The shape and contour of the alignment surface 1242 may bedetermined based upon the 3-D modeling images of the patient, acombination of two-dimensional radiographic images of the patient, or acombination of three-dimensional and two-dimensional images of apatient. For example, a patient-specific device generator may generate aprosthesis image in its final implanted position and orientation andthen generate a patient specific jig corresponding to the finalimplanted position. In such an embodiment, the anatomic alignment member1210 and the corresponding anatomic alignment surface 1212 may begenerated to align or engage with the anatomic structures of the patientnear the acetabulum while the prosthesis alignment member 1240 and thecorresponding alignment surface 1242 may be generated to align with therim and a prosthetic acetabulum when in the final implanted position. Inthis way, a doctor may use a physical patient specific jig manufacturedaccording to the final installation position of the prosthesis and thepatient's specific anatomic structure.

The various embodiments described above can be combined to providefurther embodiments. Aspects of the embodiments can be modified, ifnecessary to employ concepts of the various patents, applications andpublications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

The invention claimed is:
 1. A device for use in placing a prosthesis ina patient during joint replacement surgery, the device comprising: abody having an annular shape; a first alignment member extending outwardfrom an outer surface of the body, the first alignment member shaped toconform to an anatomic structure of the patient and mate with theanatomic structure in a single orientation; an inner surface defining anaperture through the body; and a prosthesis alignment member protrudingradially inward from the inner surface of the body, into the aperture ofthe body, the prosthesis alignment member having a surface shaped toalign with a prosthesis in an installation position on the patientduring the joint replacement surgery, the surface shape of theprosthesis alignment member based on a three-dimensional model of theposition and orientation of the prosthesis in the installation position.2. The device for use in placing a prosthesis in a patient during jointreplacement surgery of claim 1, wherein: the prosthesis alignment memberis configured to mate with and engage a rim of the prosthesis in theinstallation position.
 3. The device for use in placing a prosthesis ina patient during joint replacement surgery of claim 1, wherein: theprosthesis alignment member is configured to mate with an inner surfaceof the prosthesis in the installation position.
 4. The device for use inplacing a prosthesis in a patient during joint replacement surgery ofclaim 1, wherein: the prosthesis alignment member is configured to matewith an arc of a rim of the prosthesis in the installation position. 5.The device for use in placing a prosthesis in a patient during jointreplacement surgery of claim 1, wherein: the prosthesis alignment memberis configured to mate with a circumference of a rim of the prosthesis inthe installation position.
 6. The device for use in placing a prosthesisin a patient during joint replacement surgery of claim 1, wherein: theprosthesis alignment member is one of a plurality of prosthesisalignment members extending from the inner surface of the body andconfigured to mate with the prosthesis in the installation position. 7.The device for use in placing a prosthesis in a patient during jointreplacement surgery of claim 6, wherein: one or more of the plurality ofalignment members is configured to mate with a working surface of theprosthesis in the installation position.
 8. The device for use inplacing a prosthesis in a patient during joint replacement surgery ofclaim 6, wherein: one or more of the plurality of alignment members isconfigured to mate with a rim of the prosthesis in the installationposition.
 9. The device for use in placing a prosthesis in a patientduring joint replacement surgery of claim 1, wherein: the anatomicalignment member extends around the outer surface of the body.